Protein-protein contacts in the glucocorticoid receptor homodimer influence its DNA binding properties.
We have investigated the influence of the N-terminal domain of the 94-kDa glucocorticoid receptor on the DNA:receptor interaction. An alpha-chymotrypsin-induced 39-kDa receptor fragment, containing the hormone and DNA binding domains, binds DNA with a reduced specificity compared to the intact 94-kDa receptor. Various footprinting assays did not reveal any qualitative differences when comparing the DNA contact points made by the two different receptor entities. Like the intact receptor, the 39-kDa receptor fragment binds as a dimer to DNA. Glutaraldehyde cross-linking demonstrated a difference in the protein:protein contacts of the two homodimers. Furthermore, the dimeric 94-kDa receptor did not recognize a half-DNA site, while the dissociated 94-kDa receptor dimer and the dimeric 39-kDa receptor fragment allowed binding to such a site. These results suggest that the loss of the N-terminal domain of the receptor affects the steric arrangement and/or rigidity of the two DNA binding domains of the receptor homodimer, resulting in a decreased DNA binding specificity of the 39-kDa receptor fragment.
Eriksson
P
P
Department of Molecular Genetics, Medical Nobel Institute, Stockholm, Sweden.
Wrange
O
O
D000818:Animals; D001482:Base Composition; D001483:Base Sequence; D001665:Binding Sites; D002918:Chymotrypsin; D004247:DNA / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D005090:Exodeoxyribonucleases; D008099:Liver / Q000378:metabolism*; D046911:Macromolecular Substances; D008958:Models, Molecular; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009690:Nucleic Acid Conformation; D009710:Nucleotide Mapping; D010446:Peptide Fragments / Q000302:isolation & purification / Q000378:metabolism; D051381:Rats; D011965:Receptors, Glucocorticoid / Q000302:isolation & purification / Q000378:metabolism*; D014222:Triamcinolone Acetonide / Q000378:metabolism
D004268:DNA-Binding Proteins; D046911:Macromolecular Substances; D010446:Peptide Fragments; D011965:Receptors, Glucocorticoid; D004247:DNA; D005090:Exodeoxyribonucleases; C020133:exodeoxyribonuclease III; D002918:Chymotrypsin; D014222:Triamcinolone Acetonide